Method for securing shaft of cam follower device for valve action mechanism

Abstract

A method of securing a shaft of a cam follower device for a valve action mechanism is provided such that after both ends of the shaft are engaged in an interference relationship in the through-holes which are formed in alignment in a pair of separated support walls provided opposing the cam to receive the action of a cam, the diameter at both ends of the shaft is expanded and the opposite ends of the shaft are caulked or crimped at the inner peripheral surface of the through-holes, and then both ends of the shaft are further expanded throughout the entire periphery thereof and inset or wedged into the inner peripheral surface of the through-holes.

What is claimed is: 
     
       1. A method of assembling a cam follower device which includes a pair of parallel support walls having mount through-holes in alignment with each other, a shaft having opposite end sections each having an end face, the end sections being fitted respectively into the mount through-holes of the support walls, and a middle section positioned axially between the end sections of the shaft, an annular rotary member provided around the middle section of the shaft, and a plurality of rollers provided between the shaft and the annular rotary member, the method comprising the steps of:   providing a cylindrical tool member to be pressed against said shaft and which has an annular projection with a double-tapered outer face having a first outer surface tapered to form a leading edge so that a wedging action is caused as the leading edge is pressed into one of the end sections through the end face of the shaft and a second outer surface tapered in respect to said first outer surface so as to produce a relatively larger resistance to the wedging action; and   pressing the tool member against the end face of the end section of the shaft so that the leading edge of the tool member is advanced into the end section of the shaft to crimp the end section of the shaft against a support wall around a respective mount through-hole in such a manner that resistance to the wedging action is suddenly increased by abutting of the second outer surface of the tool member against the end section of the shaft whereby the leading edge is prevented from advancing too deep to affect the middle section of the shaft.   
     
     
       2. A method of assembling a cam follower device of claim 1, wherein the end sections of the shaft each have an edge to define the end face, and the end sections of the shaft are crimped in a two-step manner generally along the edge so that during said pressing step the edge of the shaft is expanded in diameter generally along the edge of said end section and is pressed onto said support wall. 
     
     
       3. A method of assembling a cam follower device of claim 1, wherein the end sections of the shaft have an edge to define the end face, and the end sections of the shaft are crimped, so that the edge of the shaft is crimped generally along the edge, and the second outer surface is formed partly around the first outer surface, so that the second outer surface is partly abutted to the end section of the shaft, whereby the shaft is prevented from rotating in the through-holes. 
     
     
       4. A method of assembling a cam follower device of claim 1, wherein the shaft is first secured in engaging relationship in the mount through-holes, and the shaft is then secured by crimping the opposite ends of the support walls, so that even in the case where a strong force is applied in a direction to cause the shaft to rotate, the shaft is prevented from rotating.